The color you see on computer monitors is different from monitor to monitor, and how you have it adjusted. I suspect our eyes are a little different too. There are so many variables it's impossible to get it exact. The only way to really see what it looks like on Mars is to go there and look with your own eyes. What I see on my computer looks fine with me, and I will not be a stickler for it to be exact. The MER team uses the filters for scientific purposes and I don't care that much if it looks perfect or not to my eyes. But that's me. You're all welcome to tweak the color to your hearts content. Have fun.